Classifier



R. s. TROTT Sept. 25, 192s cLAssIFiER Filed Feb. 7, 1922 :3 Sheets-Sheet 1 INVENTOR.

R. S. TROTT .cLAssIFIER Filed Feb. '7, 1922 5 Sheets-Sheet 2 (h M Mal -MlNVE/VTOR Sept. 25,1923.

R. S. TROTT CLASSIFIER Filed Feb, 7; 1922 3 Sheets-Sheet 5 /VENT@ R thewhole mass is merely agitated.

Patented Sept. 25, 1923.

warren stares- ROLLAND SJTRO'IT, OF DENVER, COLORADO.

CLASSIFIER.

Application filed February 7, 1922. Serial No.,534,770.

such a. classifier to give great adaptability over a wide range ofconditions as will appear below.

In the ordinary reciprocatingrake classifier, the rakes, which operatein a sloping box or vat, rake the settled material upward along theslope to the sand discharge end of the machine, which is above waterlevel.

The'lighter material and liquid overflow at the opposite end of theclassifier, the feed being put in at an intermediate point.

Between the strokes of the rakes the matcrial has a chance. to settle,and it is this settled material which the rakes move upward toward thesand dischargeend of the classifier.v

As the rakes intermittently move the settled material upward along theslope .and below the water level, a washing action takes place, tendingto clean the sand.

The time required for proper settling under these circumstancesnaturally varies with the material being treated, the percentage of sandand slimes therein, and the fineness to which it has been ground. If,with a certain material, the rakes are reciprocated so fast that thereis not enough time between strokes for proper settlilng,

or suspended material runs back as fast as the rakes move it up theslope, and hence no classification takes place.

In such a case the only thing to do is to reduce the number of strokesper minute of the rakes till enough time is given the material inquestion for proper settling between strokes.

As the amount of material the rakes canof strokes per minute, thisnaturally reduces the capacity of the classifier.

In my classifier this loss of raking capacity is made up for bylengthening the stroke of the rakes, as the number of strokes per minuteis decreased, as will be explained below. I

Hence, in my classifier, by lengthening the stroke as required, theraking capacity may be maintained the same, and the settlingrequirements of any material may be met.

This means not only good classification, but'good capacity as well,regardless of the material being treated.

I obtain these advantages bv a construction in which the rakes aresuspended from wheels that roll upon a sloping, vertically movable trackwhich is held at its lower position while the rakes are moving upwardalong the slope of the track, and-which is held at its upper positionwhile the rakes return toward the lower end of the track.

The movable track is made long enoughto stroke of the rakes, is tochange the oficenter position of the crank pin which is connected to therakes by a connecting rod. The extreme limit of travel of the rakes ineither direction may be maintained unchanged if desired by properadjustment of the connecting rod length as the stroke length is altered.

In the drawings, Figure 1 is a side elevation of my classifier, partlyin section; Figure 2 is a plan view of the same, and Figure 3' is afront elevation. Figure 4 is a fragmentary view of the modified parts ofa modified form of the track and roller connection between the rakes andthe bell cranks.

-The rakes 1 are suspended from the wheels 2, which roll back and forthupon the track 3, when driven by the connecting rod 4 and the crank pin'5.

'lhe crank pin 5 is made as an integral part of the plate 6, which isbolted to the face of the cam 7. Extra bolt holes are provided to allowthe crank pin 5 tobe shifted along the line X.X as desired to vary thelength of stroke of the rakes 1.

Any other proper method of changing the throw of the crank pin 5 may beused provided it retains the crank pin 5 some place upon the line X-X sothat its angular relation to the cam 7 will remain unchanged.

The cam 7 is mounted upon and keyed to the shaft 10, which is properlyjournaled and is revolved by gearing or any other proper method of powerdrive.

The bellcrank 12, mounted on the fulcrum 13, carries on one of its armsthe pivotally mounted lever 14, which carries the roller 1 designed -toroll upon the cam 7. The

same arm of the bellcrank 12 carriesthe clevis 15 and the adjustingscrew 12*, which bears against the lever 14, The other arm of thebellcrank 12 is provided with the clevis 16.

The bellcrank 17 is provided with the clevis 18, the clevis 19 and thefulcrum 20, upon which it is mounted.

The adjustable link 21 is provided with a clevis at its lower end andpasses through the pin 18 in the clevis 18, theyelfective length of thelink being adjustable by movement of the threaded nut 21.

The track 3, preferably of circular cross section, is at its one endpivotally mounted in the clevis of the adjustable link 21, and at itsopposite end it is pivotally mounted in the clevis 15 of the bellcrank12.

The clevis 19 of the bellcrank 17, is pivota-lly connected to the clevis16 of the bellcrank 12 by the rod 22, which is provided with theturnbuckle 22, or withother means to adjust the rod length.

The tongue and clevis of the above mentioned pivotal connections may bereversed, or other proper form of pivots may employed if desired.

The wheels 2 put the weight of the rakes on the track 3, and thusthrough thebellcrank 12, the adjusting screw 12 and the lever 14 causethe roller 14 to bear against the cam 7, not only through the weightsupported by the bellcrank 12, but also through the action of theadjustable link 21, the bellcrank 17 and the rod 22 in supporting theopposite end of the track 3 and that end of the rakes.

It will now .be seen that the cam 7 is.de-'

signed to raise both ends of the track 3 when the rake 1 is at the upperend of its travel, and to keep it raised till the rake 1 has returned tothe lower end of its travel, when the cam 7 then lowers the track 3 andkeeps it in that position till the rake 1 has again reached the upperlimit of its travel on the track 3, and so on. I

It will be noted that the cam 7 has a very simple duty to perform, andhence has no contours likelyto menace long life and smooth running. 1 1v The height of both ends of the track 3 may be altered as desired bythe proper adjustment of the screw 12. And the angle of the track 3 withthe slope of the vat 23 may be altered as desiredby proper adjust.

assess;

ment of the nut 21 of the adjustable link 21, or by the adjustment ofthe length of the rod 22 by the turnbuckle 22.

These adjustments may be required under operating conditions, and theyserve to give 7 the machine even more adaptability to meet any and allrequirements of the materials to be treated.

At the'sand discharge end of the classifier, between the water level andthe sand discharge lip 23 there is provided in the floor of the vat 23,the porous screen 24.

It is well known that a filter in this position will clog up and becomepractically useless in a very few minutes, for which reason there arenone in use at the present time.

In my invention I use a screen that is porous; that is, the holesthrough it are perhaps several times the size of the largest particlesfed to the classifier.

The result is that as the sand is raked up the slope and upon thisporous screen, leaking of sand through the said screen takes place tillthe next stroke of the rakes carries it up over the discharge lip 23,and brings a new quantity of sand upon the screen.

I prefer that this porous screen 24 be made i of a steel plate providedwith slots or holes, though certain types of wire screens may be used ifdesired, or any other porous mediuuu It has been observed that inreciprocating rake classifiers most of the water in the sand at thedischarge lip lies in the first half inch directly above the fioor ofthe vat. That is, in its movement by the rakes up along the slope fromthe water level the water in the sand quickly drains down to the bottomof the sand bed, as it naturallywould in any sand bed.

It is this fact that has caused so many trials of a filter in the floorof a classifier, all of which trials have resulted in failure becausethe filter could not be kept clean, but quickly became so'clogged as tobe practically useless for drying the sand.

So, in my porous screen I do not attempt to extract the moisture fromthe sand, but merely separate the bottom of the sand bed which is wet,from the top of the sand bed 1 which is relatively dry.

In my porous screen, the action f the rakes in raking the-sand upward,forces a the number of strokes per minute of the rakes. Ifthisrelationship is obtained, the sand seems to run through the openings ofthe screen a certain amount and then forms a bridge over each hole,which greatly checks the amount of sand that passes through the screen.This forms a. sort of moving sand filter through which moisture may passdown to my porous screen in the short time remaining before the nextrake stroke.

The sand and water which thus pass through my porous screen is returnedby the sand pump 25 or other such means to the feed launder 26, and thusback to the classifier, or may be returned direct to the classifierwithout entering the feed launder 26.

So the leakage through my porous screen, both water and sand, is inclosed circuit with the classifier, and only the dryer portionof thesand raked up the slope is allowed to pass over the sand discharge lip23, after the wet portionof the sand has been separated from it.

WVhen slow settling material is being treated, the crank pin 5 may bemoved along the line XX till the stroke of the rakes is long enough tmake the required sand delivery at the low number of strokes per minutere quired to give the material time to settle between strokes.

In general, the slower the settling, the finer is the material, and theslower the contained water will drain to the bottom of the sand bed.

But, in my classifier, this material may be moved by a long stroke ofthe rakes which will not only give along time between strokes to permitsettling, but will also give a long time between strokes topermit properdraining of the Water to the bottom of the sand bed.

Thus, my classifier may meet both the settling and the dryingrequirements of such material by proper adjustment'of the stroke of therakes, and the number of strokes per minute.

My porous screen may be inclosed and put under a vacuum if desired, butI prefer the construction shown, as the desired drying capacity, orseparation of the wet sand from that relatively dry may generally beobtained by variation of the size of the screen openings and the numberof strokes of the The overflow from the classifier takes place over theedge 27 of the vat 23, and over the edges 28 of the launder 29, which islet into the sides of the vat 23 till ne or both edges are ator. nearthe level of theedge 27, the passage of the launder 29 through ,thewalls of the vat 23 being made watertight. This arrangement gives a.great length of overflowedge and prevents channels and localizedcurrents when a great quan'tity'of material is being handled by theclassifier.

The above described classifier is of the single type, but naturally itmay be made in the duplex type as well, by the combination of two singleclassifiers and preferably alternate movements f their rakes, as anyoneversed in classifierswill understand.

Iam aware that the track 3 may be mount ed integral with the rakes 1,and the rollers 2 may be mounted in the clevis 18 of the bellcrankylTand in the clevis 15 of the bellcrank 12, so that the bellcranks willsup port the track 3 through the rollers 2, as illustrated'in Figure 4.

But, this does not depart from the essence of' my invention so I do notwish to confine the construction to the exact design described, but whatI claim as new, and desire to protect by Letters Patent, is asfollows 1. In a classifier, a sloping vat, bellcranks mounted upon saidvat, a track supported by said bellcranks, rakes supported by saidtrack,a shaft-mounted on said vat and provided with a crank pin with adjusta-ble throw, means connecting said'crank pin and said rakes toreciprocate said rakes, a lever pivoted upon one arm of one of saidbellcranks and provided with a roller, adjustment means between saidlever and the bellcrank upon which it is mounted, and means.

forming a track for said roller and operated by said shaft to actuatethe said bellcranks andraise and lower said"rakes at predeterminedpoints in their travel.

2. In a classifier, a sloping-vat. a pair of bellcranks mounted uponsaid vat, a track suported by said bellcranks, rakes supported by saidtrack, a shaft mounted on said vat and provided with a crank pin withadjustable throw, means connecting said crank and said rakes toreciprocate said rakes. a lever pivotedupon one arm of one of saidbellcranks and provided with a roller. adjustment means between saidlever and said bellcrank, adjustment means in the connection between thebellcrank and the other end of said track. and means operated by saidshaft and acting through said lever, said adjustments and saidbellcranks to raise and lower said track at predeterminedpoints in thetravel of the said rakes.

3. In a sloping tank classifier. rakes, supporting means, track androller means extending longitudinally above the center line of saidrakes and connecting them with said and roller connections and saidrakes, and a supporting means, means to raise and lpwer crankpinattached to said cam and connected said sup orting means, and means torecip to said rakes to reciprocate them.

rocate said rakes and thereby impart rela- 9. In a sloping tankclassifier, bellcranks tive movement to the track and. roller ele jpivotally mounted above the tank, a power ments of said centrallylocated track and driven cam, rakes, centrally located selfroller means.1 aligning roller and track connections be- 4. In a sloping tankclassifier, rakes, suptween the longitudinal center line of said portingmeans, .track and roller means cenrakes and said bellcranks, meansoperated 1. ,trally located above the longitudinal center by said camand operating said bellcranks to line of said rakes and connecting themwith raise and lower said connections and said said supporting means,means to reciprocate rakes, and means mounted on said cam and saidrakes-and to vary the length of said connected to said rakes toreciprocate them. reciprocation, and means to raise and lower 10. n-asloping tank classifier, bellcranks said supporting means atpredetermined pivotally mounted above the tank, a power points in thetravel of said rakes. driven cam, rakes, self-aligning roller and 5. Ina classifier, a vat, bellcranks mount- Z track connections between thelongitudinal ed above the vat, rakes, roller and track concenter line ofsaid rakes and said bellcranks,

nections in a single line above the longitudimeans operated by said camand operating 20 nal center line of said rakes and forming a saidbellcranks to raise and lower said conself-aligning connection betweensaid rakes nections and said rakes, and means mounted and saidbellcranks, means to reciprocate on said cam and connected to'said rakesto said rakes and to adjust the travel of said reciprocate them.reciprocation, and means to oscillate said 11.--In asloping tankclassifier, bellcra'nks 25 bellcranks and thereby raise and lower saidpivotally mounted above the tank, a power rakes at predetermined pointsin their redri en Cam, rakes, self-aligning roller and ciprocation.track connections between the longitudinal 6. In a classifier, a slopingvat, a tr k center line of said rakes and said-bellcranks, mountedcentrally above said vat, rakes, ns operated by Said cam and operatingbellcranks mounted abov said vat, roller said bellcranks to oscillatethem, and means as adapted to cooperate with said track and n sa d can'land c nnect d to said rakes to xform a central, self-aligning connectionbe reciprocate them.

' tween said rakes and said bellcranks, means 12 III & C sifi a ng emovable rack, to reciprocate said rakes, and means to oscilmeans f r v gh rack, and a movable 35 late said bellcranks and raise and lower said as ppor ed by the track.

self-aligning connection at predetermined 13, In a classifier, asloping, single, movpoints in the travel of said rakes. able track,means for bodily lifting'the track 7, I a l ifi a l i b tt d t k atintervals, and a'movable rake supported provided with an overflow, asand discharge y h trackabove the level of the overflow, and feed 14. Ina classifier, a sloping, single, movmeans intermediate the overflow andthe able k, means v y g the slope 0f sand discharge, bellcrankspivotally mounted Y the track and a movablerake supported by above saidtank, a power driven cam, rakes, the track track and roller meanslocated above the I a classifier, a Single movable. track, longitudinalcenter line ot'said rakes and means for moving the track and a movableforming a self-aligning connection between rake supported by the track,in combination the rakes and the said bellcranks, means With a troughadjacent the bottom of which operated by said cam and operating said herake travels in one of its movements. bellcranks to raise and lower saidrakes, a 16. In a classifier, a sloping, single, mov- 50 crankpinattached to the side of said cam able track. meansfor bodily lifting thetrack and radially adjustable thereon. and means at intervals, and amovable rake supported connecting said crankpin and'said rakes to by thetrack, in combination with asloping reciprocate said rakes. trough,adjacent the bottom of which the 8. In a classifier, a sloping bottomedtank rake traverses in one of its movements.

. provided with an overflow. a sand'discharge 17. In a classifier, asingle movable track, 1 0

above the level of the overflow, and feed means for moving the track,amovable rake means intermediate the overflow and the supported by thetrack and means to vary sand discharge, bellcranks pivotally mountthelength of the movement of the rake.

ed above said tank. a power driven cam, 18. In a classifier, a. sloping,single, movrakes, track and roller means located above able track, meansfor bodily lifting thetrack 1 the longitudinal center line of said rakesat intervals. and a movable rake supported and forming a self-aligningonnection be-' by the track' and provided with meansvto tween the rakesand the said bellcranks, vary the length of its movement. means operatedby said cam and operating 19. In a classifier, a sloping single mov--said bellcranks to raise and lower said track able track, means forvarying the slope of the track, and a movable rake supported by thetrackand provided with means to vary the length of its movement.

20. In a sloping tank classifier, a tank, rakes, supporting meansmounted upon said tank, track and roller means extending longitudinallyabove said rakes and connecting-them with said supporting means, meansto raise and'lower said supporting means, and means to reciprocate saidrakes and thereby impart. relative movement to the track and rollerelements of said track and roller means.

21, In a sloping tank classifier, rakes, supporting means, track androller means located above the said rakes and connecting them with saidsupporting means, means to reciprocate said rakes and to vary the lengthof said reciprocation, and means to raise and lower said supportingmeans at predetermined points in the travel of said rakes.

22. In a classifier, a vat, bellcranks mountabove the vat, rakes, rollerand track connections above said rakes and form ing a self-aligningconnection between said rakes and said bellcranks, means to reciprocatesaid rakes and to adjust the travel of said reciprocation, and means tooscillate said bellcranks and thereby raise and lower said rakesatpredetermined points in their reeiprocation.

23. In a sloping tank classifier, bellcranks pivotally mounted above thetank, a power driven cam, rakes, self-.a'li 'ing roller and i: saidrakes and the said bellcrank s, means operated by said cam and operatingsaid bell-cranks to raise and lower said connections and said rakes,

,and means mounted on said cam and con-v nected to said rakes toreciprocate them.

24. In a sloping tank classifier, bellcranks pivotally mounted above thetank, a power driven cam, rakes, self-aligning roller and trackconnections between said rakes and said bellcranks, means operated bysaidcam and operating said bellcranks to oscillate them, and means onsaid cam and connectedto said rakes to ciprocation;

25; The process of classifying material containing granular elements toobtain a vary the length of said re relatively dry discharge, whichconsists of introducing the material into a sloping tank provided withan overflow for liquid and the finer parts of said material moving themalayer-will be delivered. beyond said pervious member.

26. The process of classifying material containing granular elements toobtain. a relatively clean, dry discharge, which consists of introducingthe material tank provided'with an overflow for liquid and the finerparts of said material, moving the material which settles, slope of thetank and above the level of said overflow, and then over a perviousmember, the perforations of which are larger than the largest granulesof said lower wet layer of said material will pass through said perviousmember and'be conveyedl back. to said tank, and the relatively drymaterial above said lower layer will be delivered beyond said perviousmember,

27. The process of containing granular elements to obtain a relativelydry-discharge, which consists of introducing the material intoa tankprovided with a liquid bath, '-moving the material which settles, apervious member, the perforations .of which are larger than the largest.granules of said material, whereby a lower wet layer of said materialwill pas through said pervious member, and the relatively dry masaidlower layer will be deinto a slopingclassifying material out of the bathand then over.

upward along the v material, whereby a atively dry discharge, whichconsists of introducing the material into a tank provided with a liquidbath, moving the material which settles, out-of the bath and then over apervious member, the perforations of which are larger than the largestgranules of said material, whereby a lower wet layer of said materialwill pass throughsaid pervious member and bebath, and the relatively drymaterial above the said lower layer'will be delivered beyond saidpervious member.

ROLLAND S. TROTT.

conveyed back to the

